Method of refining polymerized rosin and polymerized rosin esters



Patented Sept. 14, 1943 c1611 E. Tyler, HattieSburgQMiSs andHarold R. Monfort, Wilmington, DeL; assignors toHercorporation"of-Delaware cules Powdei- Company, Wilming No Drawing. Application Marclrl, 1941',

Serial No. 381,384

1 j 9iClaims. (01. 260 -97) This invention relates -to polymerized rosins and polymerized rosin esters and more particularly to a process for the refining of such maa terials. y H

The polymerization of rosin and rosin esters with sulfuric'acid or organic substituted sulfuric acids hasbeenfdescribed in the art. Suchcatalyst's'comprise very favorable materials for ef fecting an increase in melting point of the rosin or rosin ester. Such catalysts, although highly favorable from the above standpoint, suffer the disadvantage of discoloring the rosin or rosin ester to a certain extent and of contaminating the polymerized product with combined sulfur. The known procedures for refining ordinary rosin have. not proved satisfactory for refining such sulfuric acid polymerized rosins and rosin esters due principally to the fact that they do not satisfactorily improve the color, because they have a tendency to decrease the melting point of the polymerized product, and'pa'rticularly becaus'eth'ey do not effectively remove all combined sulfur contamination from the polymerized material.

The presence of sulfur in free or combined form. in polymerized rosin is particularly disadvantageous in the use of the material in the production of esters, varnishes, gloss oils, metallic salts, etc. and in the use of the polymerized rosin esters in varnishes. It causes appreciable color degra dation in the polymerized product duringthe heating required in preparing such materials from the polymerized rosin or rosin ester. The sulfur at elevated temperatures combines with certain metallic impurities" forming colored sulfides and thus in some instances gives rise to in a substantially quantitative yield basedon the veryseverecolorformation. The amountof sul I fur which causes these disturbingcolor phe-v nomena is very small. {I'huara sulfuric acid polymerized rosin having as little as 0.015% of sulfur discolors perceptibly during the heating required to form esters, varnishes, metallic salts, etc. Removal of sulfur down to about this; amount has been possible by prior purification; procedures, but it has been impossible to go belowthis amount and therefore to produce a com pletely satisfactory sulfuric acid polymerized rosin or rosin ester.. t

It is an object of'this invention to provide an improved procedure for refining a polymerized rosin or rosin ester obtained by use of asulfuric acid type catalyst. It is a further objectto provide an'improvedprocess of refining such poly merized products which is extremely simple and economical.qIt is another'objectto providea.

polymerized rosin treated. It is a-further objectto provide as a new composition a;sulfuric acid polymerized rosin orrosin ester-which will not discoloronheating-with metals and which has 'a "sulfur content less tha about =0.015%.;

Theabove objects are accomplished ir accord ar1cev with this: invention by subjecting-a .;po l ymerized rosin orga polymerized rosin ester obtained by use-of a sulfuric. -acid type polymeriza tion catalyst to treatment with molecul'ar h ydro gen at a temperature within the; range of.

about 250 to about 325 10., witl fout'sub stantial distillation of the polymerizedro'sin or. rosin ester.

By means of such treatment the color of the polym'er-ized product is materially improved and the sulfur impurity is practically entirely-eliminated. The refinedv polymerized rosin or rosin ester is obtainedwithpractically no lossirr yield and with substantially no decrease in melting point.

The polymerized rosins or polymerized rosin esters which maybe treated by the refining process described in accordanoewith this invention may be-those derived'from any of the various grades of wood or gum rosin or; esters thereof They comprise 'thepolymerized rosins on-,rosin esters obtained withuse of a sulfuric acidtypej polymerization catalyst, for eicample sulfuric acid, organic substitutedsulfuricacids as ethyl sulfuric 'acid, acetyl' sulfuric acid, phenylsulfuric acid, etc., or acid sludge. catalysts formed by treatment" of rosin with sulfuricacid such as described in an application, Serial No. 328,864,

filed April 10, 194o, by"c1 e 1i Tyler. Catalysts ofthe above typeare broadly interpreted for the;

purposes of this inventionlas sulfuric-acid type catalysts and all providepolymerized rosins and rosin'e'sters which contain thefobjectionabl'e and .very difiicultly removable sulfur impurity;

The polymerized I rosin esters which may treated in accordancewith this invention'to provide the above-described improvements will in elude"polymerizedfmonohydric as well as poly hydric alcohol esters'which have been polymerized t by the sulfuricTacidqtype catalysts mentioned above. Thus they will include polymerized forms.

of the methyl, ethyl, propyl, butyl, ethylene gly-- col, propylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, glycerol, pentaerythritol, etc. esters of the various rosins. Alternatively, the process may be carried outon the equivalent esters obtained byesterific'ationof process for refining polymerized rosin obtained.

polymerized rosin produced as above with alcohols such as those named above. The polymerization by any of these methods is usually carried out by treatment of the rosin or rosin ester dissolved in some suitable organic solvent.

The polymerlzedrosins or rosin esters, which may be refined in accordance with the above process will be those having a drop melting pointv from about 5 C. to about 100 C. above the melting point of the original rosin in the polymerization.

The treatment of polymerized rosin or polymerizedrosin esters with molecular hydrogen is preferably performed after thesolventl and'catalyst have been removed from the polymerized;

material. The treatment is preferably carried out by heating the polymerized material within the above temperature range and simultaneously passing a stream of molecular hydrogen through the molten material. The velocity of the hydrogen passed through the polymerized rosin or rosin ester will be 'adjusted so astdpreve'ntany sub stantial distillation of the polymerized" material.

The time or treatmentnece'ss'ary t'oprov'ide the desiredrefining will depend upon a number of factors such as the particular product being treated; the temperature of treatment, the amount of gas employed, as "well as otherles's important variables. The preferable temperature of treatment will be about 250 to about 280 C. An ideaof the time-of treatment will be gained from the following illustrations. Thus, for example, with a polymerized rosin-obtained by use of an acid sludge Catalyst obtained: by action; of V concentrated sulfuric acid on wood rosin, as described in the application, Serial No. 328,864 rer ferred to above, treatment at 250 C. for min;- utes' will provide a material color improvement and will reduce the sulfur content to below 0.010%, whereas at a temperature of 280 C. a

time of-lO minuteswill give a comparable product with use of'the same amount of hydrogen. In

general; the'ti me requiredto provide asatisfactorily're'fined product will fall within th ran e of'a'bout 5-niinutesto about one hour.

' The above treatmentof polymerized resins and polymerized rosin esters may be carried out batch-wise or a continuous manner. In car;- rying out the-treatmentcontinuously the poly:

merized materialto be refinedmaypbe passed through a heat-exchanger or other suitable de vice in contact with hydrogen in sucha manner as to provide the desired time of contact.

As illustrative of the improved process of refining polymerized rosin or polymerized rosin various modes of carrying out the invention.

Colors shown are expressed either as the color of a inch cubeaccording to the U. S. Rosin Color Standards or asthe Lovibond glass colors. As a test for efiectiveness' ofsulfur rernoval, the refined product is heated to 260 C. and Z per cent of its wei ht or lithargejthen ended and the heat} ing continued in an inert atmosphereof carbon dioxide or nitrogen to 300 C.'and the temperature held at 300 C. for 5 minutes. The color of the cooled product is then determined; With a sulfur content above 0,0153% very pronounced discoloration occurs.

, xam e I V A polymerized rosin was prepared by the continuous procedure described in the application; Serial No."328,86 4= filed April 10,- 1940; by Clell E.

o nester. usedv Tyler involving use of a sludge obtained by treatment of rosin with sulfuric acid as a catalyst. Thus, a per cent solution of K wood rosin in benzol Was treated with about 15 per cent its Weight 0f 97 percent sulfuric acid at a't'emperatur e of 15 to.1 8," C. to: form an acid sludge catalyst. A continuous flow of the rosin solution was then contacted with the above acid sludge catalyst at a temperature of 15 to 18 C. 1.

at such a rateas to provide contact suflicient to giveapolym'erized rosin of melting point of about 1 00. C. The polymerized rosin solution was then hcatedwith one-third its weight of sulfuric acid atBQ C. for one hour to permit water Washing without; emulsion formation and the polymerizedrosin solutionthen Washed with water to; remove the sulfuric acid. The benzol was then evaporated under reduced pressure. The

esters in accordance with this invention, the ex.- amples whichfollow are cited 'as typical of the coloroflthe resulting product was 40 Amber-{6.75 Red. Theabove polymerized rosin was heated a I emperat r 0127 Q19 1 fiitee i min while at the same time passing a stream of molecular hydrogen'through the rosin. The resulting product was of a considerably improved color andshowed substantially complete. absence cesium. The analysis of the polymerized rosin before and after the heat treatment. was asfole lows;

Acid number Melting point (dro Color- Sulfur content. Color 'With 2% litharge 0.008%. 40 Amber.

The yield was substantially quantitative.

Example II T e.sam gun ne .n l m r d 'osm s c as. in liar-ample Twas heated at 300. C, forlfi minutes, 1 atv the, same. time; passin'g iagstream of molecular hydrogen through the rosin. The

analysis of the polymerized rosin before and after the hydrogen treatment was as follows: I

\ Before, After 100.5" C 1019 C. 40 Amber-k5 75 R d 25 Amber Black 27- Amber 0.007%;

- 'E pj ja 'lf The process or-exam le II wasrepeated. but; with use of a temperature 01265 Grand a/time of 251 minutes. The effect; of the treatment on color and sulfur co'n-tent is shown below:

ample I l was subjected-to vacuum {distillation at about 1 pressure and-with a bath temperature' of 5 about 250 -280-C until approximately 50-%{ of :the polymerized-rosin-hadydistillcd off,- I I leaving a more highly polymerized residue. The

residue, amountingto 50% of the original-product, had the following analysis: a

M01. wt. (Rast) 590 (original rosin 320) Sulfur "per cent 0.003

' Example V A polymerized rosin was prepared by adding 100 parts by weight of 85% sulfuric acid to a solution of 400 parts by weight of WG gum rosin in 140 parts by weight of narrow range gasoline of boiling range 90 to 120 C. with agitation over a period of hour, holding the temperature at 30 to 32 C'. The reaction mixture was then poured into 650 parts by weight of the narrow range gasoline with agitation. The gasoline solution was then washed with water to remove the sulfuric acid, and the gasoline evaporated by distillation under reduced pressure. The polymerized rosin obtained was then refined by heating at 300 C. for 30 minutes-while at the same time passing a stream of molecular hydrogen into thematerial without causing distillation of thepolymerized rosin. The analysis of the polymerized rosin before and after the refining treatment was as follows:

Before After Acid number 142 135 Melting point (drop) .O 120 116 01 WG X 0. 06 0. 01

Example VI K Wood rosin was polymerized by adding 100 parts by weight of crude acetyl sulfuric acid to 500 partsby weight of a 35% solution of K wood rosin in benzene over a period'of 10 minutes with agitation, the temperature being held at to C. The agitation was continued'for 1% hours at 20 C., the solution then allowed to separate and the benzene solution decanted from the sludge. The solution was then washed with water and the solvent evaporated under reduced pressure. The polymerized rosin obtained was heated at 290 C. for 10 minutes while passing a stream of molecular hydrogen into the material. A substantially quantitative yield of refined polymerized rosin resulted. Comparison of the product before and after the heat treatment is shown in the following table:

Before After ff f ta s 32 32 e ting poin rop Color I WG Sulfur per cent. 0.020 0.012

Example VII refined by heating at 300 C. for 20 minutes while passing molecular-hydrogen through the material. The yield was substantially quantitative. The effect of the treatment is shown by i the following comparison. of. the polymerized ester gum before and after the heat treatment:

Before After The polymerized rosins and rosin esters of improved color and reduced sulfur content obtained in accordance with this invention will be found 'to' be considerably more useful in commercial applications, such as in the 'production ofvarnishes, metallic resinates, etc. It is to'be understood that the term refining used throughout this invention relates particularly to the color improvement and sulfur removal and not necessarily toia separation; of the polymerized rosin or rosin ester into light-colored and dark-colored fractions. r I

It will be understood that the details and examples hereinbefore set forth are illustrative only, and that the invention as broadly described and claimed is in no -way limited-thereby. Y Whatwe claim and desire to protect by Letters Patent is: I

1 A: method of refining "a material selected from the group consisting of polymerized rosin and polymerized rosin esters whichhave been obtained by polymerization of a rosin or rosin ester with a sulfuric acid type catalyst which includes heating the said polymerized material at a temperature within the'range of about 250C-.

to about 325 C. andat the same-time passing a thereof to provide a polymerized material having a substantially decreased sulfur content and having the same number of hydrogen atoms per molecule as the untreated material.

2. A method of refining polymerized rosin obtained by polymerization of a rosin with a sul-- 'within the range of about 250 C. to about 325 C.

and at the same time passing a stream of molecular hydrogen into the said polymerized rosin without substantial distillation thereof to provide a polymerized rosin having a substantially decreased sulfur content and having the same number of hydrogen atoms per molecule as the untreated material.

3. A method of refining polymerized rosin obtained by polymerization of a rosin with an acid sludge catalyst formed by treatment of rosin with sulfuric acid which includes heating the said polymerized rosin at a temperature within the range of about 250 C. to about 325 C. and at the same time passing a stream of molecular hydrogen into the said polymerized rosin without substantial distillation thereof to provide a polymerized rosin having a substantially decreased sulfur content and having the same number of hydrogen atoms per molecule as the untreated material.

4. A method of refining polymerized rosin obtained by polymerization of a rosin with an acid saidrpolymerized. rosin: at a temperature within the range of about250 C. toabout' 280? oyana at the same time-passing a: streamv of moleccularhydrogeninto the" saidmpolymerized rosin withouttsubstantial: distillation thereof: to provide a polymerlzedzrosin having a substantially decreased sulfur content and having the same number of hydrogen atoms per molecule as the untreated'material;

5. A method of refining a polymerized rosin ester obtained bypolymerization of a'rosin ester, with sulfuric acid, as a catalyst. which includes heating the said polymerized rosin ester at a temperature within the'range of about 250 C. toabout, 325 C). and at the same'time passing; a stream of molecular hydrogen-into the said polymerized rosin without-"substantial distillation thereof to. provide a polymerizedrosinester having a substantially decreased-z sulfur content and having the same number of hydrogen' atomspper molecule as the untreated polymerized rosin ester; i p

6.; Amethod of refining polymerized rosin ob,- tained by polymerization of; a rosinrlwith a sulfuric acid type catalyst which includesheating the said polymerized rosin at; a temperature withinthe range oft-about 250 C. to about325 C. for, aperiod of.-time from aboutrfive minutesto about one hourand at thesametimepassing a stream of molecular; hydrogen into-theJ-said polymerized rosin without substantial distillation thereof to provide a polymerized rosin-having a substantially decreasedsulfur content and having the same number. of hydrogen atoms per molecule as the untreated-material.-

7. A methodof:refiningzpolymerizedrosin obtained by polymerization of;a-rosin,with a sul-, furic acid type catalyst which includes, heating the said polymerized rosin at, a temperature withinth'e'range' ofiabout 250 C. to about 280C. for a period of time from about fiverminutes; to about one hour and at the same time passing, a stream of molecular hydrogen into the said polymerized rosin without substantial distillation thereof to. provide a polymerized rosin having a substantially decreased'sulfur content and having the same number of hydrogen atoms per molecule as the untreated material.

8.- A, method of refining.polymerized-rosin 0btain edt'by polymerization of a rosin with anacid sludge catalyst formed by treatment of rosin With. sulfuric acid Which includes heating the said polymerized rosin-vat a temperature within the range of about 250 C. to about 325 C(for a period of time from about five minutes'to about one hour andatthesame time passing a stream ofmolecular hydrogen into the said polymerized rosin without substantial distillation thereof to provide a polymerized rosin having a substantially decreased sulfur content and havingthe same number of hydrogen atoms per molecule as the untreated material.

l 9. Amethodof refining polymerized rosin obtainedby polymerization of av rosin. with an acid sludge catalyst formed 'by. treatment ofv rosin with sulfuric acid which includesheating the said polymerized rosin at a. temperature within the range of about 250 C. to about 280 C. for a period of time from about five minutes to about one hour and at the same time passing a v stream of molecular hydrogen into the said polymerized rosinwithout substantialdistillation thereof 'to provide a polymerized rosin having a substantially decreased sulfur content and having the sametnumber .of hydrogen atoms per molecule as the untreatedmaterial.

CLELLE. TYLER. HAROLD R.- MONEORT. 

